Abstract: This document provides a method of determining an absolute position of a diver, comprising: providing a dive leader unit having a GPS receiver and an underwater acoustic modem configured to retransmit GPS coordinates of the dive leader unit under water, providing the diver with a monitoring unit comprising several microphones so that it is possible to detect a direction of the dive leader unit, pairing the monitoring unit to the dive leader unit to form a communication network so as to identify differences between system clocks of the dive leader unit and the monitoring unit and make it possible to calculate a distance from the dive leader unit to the monitoring unit.

Abstract: This document provides a method of determining an absolute position of a diver, comprising: providing a dive leader unit having a GPS receiver and an underwater acoustic modem configured to retransmit GPS coordinates of the dive leader unit under water, providing the diver with a monitoring unit comprising several microphones so that it is possible to detect a direction of the dive leader unit, pairing the monitoring unit to the dive leader unit to form a communication network so as to identify differences between system clocks of the dive leader unit and the monitoring unit and make it possible to calculate a distance from the dive leader unit to the monitoring unit.

Abstract: Methods, systems and computer programs can electronically provide a visual comparison of rendered 3-D medical images. The methods include: (a) providing first and second 3-D medical digital images of a patient on at least one display; (b) electronically altering a visualization of the first 3-D image on the at least one display; and (c) automatically electronically synchronizing visualization of the second 3-D image responsive to the altering of the first 3-D image.